Ladies and gentlemen, good morning and welcome to CSL's half year results call for fiscal 2021. It's Mark Dehring speaking, and joining me online is Paul Perreault, CSL's Chief Executive Officer, and John Levy, who is our Interim Chief Financial Officer. As with past practice, Paul will provide an overview of the results and operations, and then John will provide some additional detail on the financials. We'll move to Q&A. Look, with a view to giving everyone an opportunity to ask questions, could you please limit your questions to two? If you do have further questions, you are, of course, welcome to rejoin the queue. Please note this briefing is being webcast. Lastly, before we start, I draw your attention to the forward statement disclaimer contained in the slide deck. I'll now pass you over to CEO Paul Perreault. Over to you, Paul.
Thanks, Mark. Good morning and thank you for joining today's review of CSL's first half year results for 2021. As usual, I will provide, as Mark said, an overview of the results and the highlights. I'll hand over to John, our interim Chief Financial Officer, who will provide more on the detailed financials and conclude with an update on our outlook. As Mark mentioned, of course, always happy to take your questions. With that, let's move on to slide three, which is our first half 2021 performance. I'm very pleased to report that CSL delivered a very strong first half, with revenue up 15% at constant currency and net profit after tax up 44% at constant currency. This is an excellent performance, especially given the difficult and uncertain environment we've all faced with COVID-19.
This result is not only a reflection of CSL's diversified and resilient business model, but mostly our dedicated employees who've remained focused on delivering on our promise to patients and to public health around the world. Some of the first half's highlights are for CSL Behring. Earnings before tax and interest was up 24%. This was driven by strong performance of HIZENTRA, our market-leading subcutaneous IG product, which was up 19%. Albumin sales grew 93% due to the successful transition to our own distribution model in China. HAEGARDA continues to show solid growth and increased 16%. CSL Behring has also been very busy manufacturing COVID-19 vaccine for the Australian government at our Broadmeadows facility. Our influenza vaccine business, Seqirus, delivered an exceptionally strong performance with its EBIT more than doubling to USD 693 million. Sales of seasonal influenza vaccines were exceptionally strong at 44%.
The business achieved a strong increase in its gross margin due to its high value and differentiated product portfolio. We also announced for Seqirus to construct a new world-class biotech manufacturing facility in Melbourne, Australia. COVID-19 has certainly presented us and our industry with some challenges. However, we ensured our critical operations were well managed and maintained, a real credit to our people that are right across the CSL group. Later, I'll review details on how COVID-19 impacted our business. At a high level, I would say the pandemic has tempered the performance of CSL Behring whilst boosting the performance of Seqirus. Plasma collections have continued to be challenging. We have actively put multiple initiatives in place and starting to see monthly improvements. Despite this challenging environment, CSL is well-placed to emerge even stronger when the COVID-19 crisis recedes.
On to the next slide, where we have CSL Behring sales by therapeutic areas. The portfolio recorded overall sales growth of 11% at constant currency. Immunoglobulins, our core franchise, was up 7%. As I mentioned earlier, albumin was up 93%. Hemophilia was up 1%, with specialty products up 3%. I'll go into more detail with each of these shortly. In terms of the geographic split, you can see the broad reach of CSL Behring sales with our two key markets, North America and Europe. All regions recorded solid growth, with Asia Pacific up 79% as a result of the strong growth in albumin in China. Immunoglobulins on slide five. Demand for IG continues to be robust, driven by chronic indications, primary immune, and secondary immune deficiencies, as well as CIDP. Despite those challenges that I mentioned associated with COVID-19, our IG franchise still grew at 7%.
This was led by strong growth in HIZENTRA, which I mentioned earlier was up 19%. In August last year, I said we were seeing early signs that COVID-19 was driving increased usages of HIZENTRA. This has really come through strongly in the six months to December, given the preference for home treatment and the innovative nature of this product. HIZENTRA is an attractive option for patients. It gives them the convenience to self-administer at home, and with its other features such as flexible dosing and prefilled syringes. HIZENTRA assists patients to better control their disease state, even more so than with the COVID-19 restrictions. HIZENTRA has also seen a continued uptake for the treatment of CIDP in the U.S. HIZENTRA continues to build its leadership position. Its relatively new orphan drug exclusivity for CIDP makes it the only sub-Q product with a CIDP label in the United States.
More than 60% of our priority target physicians have now adopted HIZENTRA to treat CIDP patients. On the IVIG side, PRIVIGEN grew modestly. Disruptions and delays in infusion centers as a result of stay-at-home orders and preference for home treatments such as HIZENTRA, and the tightness of plasma supply have all tempered PRIVIGEN's growth. As many of you know, IG supply was tight even before the pandemic. As global IG demand remains strong, this tightness of supply has intensified during COVID. Accordingly, we are closely managing our supply chain and have taken steps to avoid any significant supply disruptions. For example, we implemented a customer order fulfillment process to ensure fair and equitable supply to current customers. Further, we are not opening many new accounts or taking new customers, but are focusing on supplying products to current customers.
As I've always said that once we have patients on product, we want to continue to supply those patients. Turning now to albumin on slide six, where sales growth was up 93%. This reflects the successful transition to our own distribution model in China, where albumin sales have now returned to a more normalized level after the one-off impact we saw in the previous year. Having our own distribution model now in place will help improve our participation in the value chain and strengthen our sales and marketing efforts in China. Excluding this change, our in-market sales of albumin in China grew in the high single digits, and we have maintained our market leadership. There has been some impact to hospital operations as a result of COVID-19 in China, but this has now returned to about 90% of normal.
Whilst the competitive environment in China has increased, demand for albumin is still expected to be in the mid to high single digits. Outside of China, we have achieved strong growth in Europe and emerging markets, whereas in the mature U.S. market, sales have been steady. Overall, excluding the GSP impact in China, sales of albumin were up modestly. Looking ahead, we expect an increase in albumin utilization in the treatment of liver cirrhosis and a preference for albumin over artificial colloids. On slide seven is hemophilia. Overall growth in the hemophilia portfolio was tempered by reduced doctor visits and patient consultations during COVID-19, simply a function of lower societal movement. Against this challenging backdrop, IDELVION, our long-acting recombinant factor IX product for hemophilia B, recorded an impressive 6% growth.
Its compelling clinical profile continues to drive patient demand, with new patients and patients switching from other factor nine products contributing to its growth. In a very competitive hemophilia A market, sales of our other recombinant coagulation product, AFSTYLA, were steady, and the market competitiveness also impacted our plasma-derived hemophilia products. This was offset to some extent to a 6% increase in Humate, which is a leading product in the U.S. for the treatment of von Willebrand disease. On to slide eight and specialty products. Overall, specialty product sales grew 3%. The standout performer was HAEGARDA, our transformational therapy for treating patients with HAE or hereditary angioedema. HAEGARDA grew strongly, up 16%, as new patients continue to take up the therapy. Also contributing were new launches in Europe and Australia, which exceeded our expectations. BERINERT was steady as patients switched to more effective prophylactic products, including HAEGARDA.
Despite this, BERINERT continues to play an important role in the HAE market, providing a safe and efficacious option for patients to treat acute attacks. The other main specialty product to record solid growth was KCENTRA, which was up 6%, and I think really impressive, but somewhat tempered by the current COVID environment. Generally speaking, the pandemic has caused a reduction in surgery and fewer incidents of trauma, both affecting the utilization of KCENTRA. In this COVID environment, the 6% was, I think, a really great result. This dynamic has also impacted other hospital products. Sales of wound healing products were down 26%, and RIASTAP was flat. For alpha-1 and total alpha-1 sales were down 7%. Sales of ZEMAIRA were down in the U.S. following a supply interruption at Kankakee.
The root cause of the issue has been identified and a plan is in place that has been approved by the regulator to move ahead to resume supply. For RESPREEZA, growth has been very strong following successful launches of the product in Europe. Turning now to plasma collections. As I mentioned earlier, COVID has presented us and continues to present us with many challenges, including our ability to collect plasma. All of our plasma collection centers have remained open and operational in the U.S. during the pandemic. However, the incidence and the spread of the virus in the U.S. has led to measures such as social distancing, stay-at-home orders, restricted mobility of donors. Combined, these have had an adverse impact on our plasma collection volumes. Additionally, the U.S. government stimulus packages have also influenced plasma collection.
As a result, our collection volumes in December 2020 were around 80% of what we collected a year earlier in December 2019. Various COVID-related hygiene measures also added pressure on the cost per liter of plasma collected. To address the lower collection rates, we have implemented a number of initiatives to increase plasma collections. I'm pleased to say they have been effective and month-on-month improvements are underway, which I'll show you on the next slide. I'd like to share some detail around the initiatives that CSL Plasma has been undertaking to increase plasma collections. We've enhanced our marketing efforts, and these include increased plasma donation awareness and education to promote the importance of plasma donation, retention and reactivation campaigns for previous donors, and referrals for family and friends. We've adopted new technologies such as a donor app, mobile phone video consent, and self-administered health history questionnaire kiosks.
Usages of these technologies are growing and providing donors with a better user experience as they enter the centers. As the rollout of COVID-19 vaccines becomes more widespread, mobility is expected to increase and lead to more foot traffic at our collection centers. CSL also led an industry initiative, which has been introduced and approved by the FDA. Now the hold period for plasma reduced by 15 days, providing an accelerated way to provide patients with the life-saving medicines they need. We've been managing our supply chain very carefully and utilizing the available finished goods wherever possible. We continue to lead the industry in new plasma collection centers. We opened 17 new centers in the first half and plan to open another 12 in the second half. We now have a network of over 280 centers globally, and our centers are the largest and the most efficient in the industry.
Finally, as our volumes recover, our cost per liter will reduce in line with the fixed cost distribution that we have across the business. If I move to slide 10 in the plasma collections graph, you can see what's happened with the plasma collections and how our initiatives have been driving growth in donors. On the graph, we have the number of donors that have come into our centers on a weekly basis. The black line is calendar 2019, the red line is 2020. As you can see, there is normally a seasonal dip in February, March, as tax refunds are distributed in the U.S. You can see where the pandemic hits and the lockdown begins in March, April, causing donor numbers to significantly fall. From here, we see the numbers starting to stabilize.
In May and then in June, our initiatives are launched, and we see an improving upward trend for the six months to December. There is a typical dip at the end of December, which is consistent with previous years, and this is due to the holiday season. In summary, plasma collections have been challenging and will continue to be challenging. We have a range of initiatives in place to counter, and we're focused on ensuring our plasma collections keep going in the right direction. As you've heard me say before, collecting plasma is one of the hardest things we do at CSL. We're determined to get our plasma collection volumes back to where we want them to be. They're improving, but they're not there yet, and we'll keep striving because our patients depend on us. Moving on to slide 11 in our influenza vaccines business, Seqirus.
Seqirus delivered an exceptionally strong performance. For the first half, Seqirus reported revenue of over $1.4 billion, a growth of 38%. This was driven by very strong sales and seasonal influenza vaccines of some 44%. The Northern Hemisphere continues to be the dominant market for Seqirus, with the U.S. and Europe accounting for over 90% of Seqirus sales in the period, with both regions delivering strong growth. Sales in Asia Pacific were down 9% or $8 million due to lower in-licensed vaccine sales as a result of COVID-19. GARDASIL sales declined since there was less international students in Australia, and also the sales of travel vaccine DUKORAL was impacted by the international travel bans. Continuing with Seqirus on the next slide, the operating highlights included the significant growth in seasonal influenza vaccines, seeing a record number of more than 100 million doses sold in the Northern Hemisphere.
COVID has been responsible for driving high demand for influenza vaccines as governments around the world look to protect their populations from influenza so that the healthcare systems are not burdened or stretched further during the crisis. Seqirus has continued to benefit from the ongoing shift in the portfolio to our differentiated and high-value influenza products, such as the cell-based vaccine FLUCELVAX, produced at Holly Springs, and our adjuvanted vaccine for the elderly market, FLUAD. Some other key milestones for Seqirus included the successful launch of FLUAD QIV in the U.S. and the relaunch of business in Germany. To cope with the increased demand, all operations were maintained during the pandemic, and capacity expansions at Holly Springs and Liverpool are well advanced. Finally, Seqirus has been instrumental in providing support for COVID-19 vaccine efforts and supplying our MF59 adjuvant to various vaccine candidates around the world.
Moving over to R&D on slide 13. There's a lot on this slide, and it shows that we have a deep pipeline in R&D underpinning our company's future growth. In the interest of time, just a couple of highlights, beginning with immunology. PRIVIGEN for the treatment of CIDP was launched in Japan. This is a great achievement in a tough market to get new indications. In hematology, uniQure announced late-breaking preliminary data from their pivotal phase III trial of EtranaDez. As you know, a product that we're in the process of acquiring. In cardiovascular and metabolic, the phase III for CSL112 continues to progress well, with now over 11,800 patients enrolled. In influenza vaccines, so that says 11,500, but I just gave you the most recent number, so there's no confusion.
In influenza vaccines, we have commenced the phase II study for our adjuvanted QIV cell vaccine. We're undertaking preclinical assessment of mRNA technology for influenza. R&D COVID-19 response on slide 14. Right from the beginning of the pandemic, we have really been focused at CSL on using our capabilities and expertise to respond to this COVID crisis. This has led us to reprioritizing our R&D projects at some significant disruption to the company's normal activities. We've redeployed and recruited 400 personnel. We've paused clinical trials, which are all now back up and running. One of the major programs that we were working on was the development of a COVID-19 vaccine with the University of Queensland.
This involves substantial activity across the company, including advanced preparation for the planned phase III trial, extensive retooling of our facilities, scaling up and producing material to produce 11 million doses to support the contract with the Australian government. Although the vaccine was progressing well, due to testing issues, the program was ultimately halted, and orders from the Australian government were canceled. In parallel to the UQ program, CSL entered into an agreement with the Australian government to manufacture 30 million doses of the Oxford University AstraZeneca COVID-19 vaccine candidate. With the UQ candidate vaccine halted, CSL pivoted quickly, and our attention was focused on accelerating the manufacture of the Oxford University AstraZeneca COVID vaccine candidate and supply an additional 20 million doses ahead of the original schedule. Manufacturing is well underway, and the first doses are planned for release in late March, having just received TGA approval.
In addition to our work on vaccines, we've also been working on COVID treatments. As a founder of the CoVIg-19 Plasma Alliance, CSL has made good progress with its partners on developing a plasma-derived hyperimmune for treating among the most severe complications resulting from COVID-19. phase III clinical trials are underway, and CSL is producing trial lots at our Swiss facility. If successful, this will become one of the earliest treatment options for hospitalized COVID-19 patients. I'm going to now hand over to John to go through some of the financials in more detail. John?
Thank you, Paul. Good morning, everybody. It's a pleasure to be talking to you and reporting this really strong half-year result. Turning to the financials, as we've reported, profit has increased both from $ 1.248 billion to $ 1.810 billion, an increase of 45%. At constant currency, profit was $ 1.794 billion, an increase of 44% after adjusting for an FX tailwind of $ 16 million. Included in the panel on the right are a number of areas that Paul has already touched on. The transition's complete to our GSP China business. Sales of albumin have normalized. Seqirus had an unbelievably strong first half, growth of differentiated products together with some manufacturing efficiencies. We have responded to the COVID-19 pandemic in a number of ways. That's impacted on our financial statements through a number of different ways. We've had impact on R&D costs.
We've incurred some costs on the re-engineering of our facilities to be able to manufacture. There have been some cost savings driven by just the changing environment in which we operate, and we obviously also have received some funding from government here in Australia in respect of the manufacture of the COVID vaccines. In total, that represents a one-off impact on net profit for the first half of around about $80 million. Turning to more detail on the financials, total revenue was up 15% on a constant currency basis to $5.653 billion. Gross profit of $3.423 billion at constant currency was up 20%, reflecting a 270 basis point improvement in gross margin. EBIT was up 42% on a constant currency basis with an associated EBIT margin expansion of 790 basis points improvement over the prior year.
The margin expansion is largely a function of Seqirus sales of new generation products. This flows down to net profit after tax and EPS, both up 44% at constant currency. Turning to cash flow, cash flow from operations was $ 2.3 billion, an 87% improvement on last year. Albeit positive in terms of percentage growth, this really is a reflection of the collections environment that Paul's just covered, with a smaller pool of plasma donors resulting in lower cash payments for plasma. Although these are at a higher unit cost in the short term. We've also implemented ongoing cost control initiatives across the business, and that has favorably impacted cash flow from operations for the period. Capital expenditure was down 13%. That's largely due to restrictions on site access around the major projects that we have across the globe, driven by the COVID pandemic.
The interim dividend is $1.04 per share, an increase of 9%. For Australian shareholders, this translates to a dividend of approximately AUD 1.34, which is down 9% on the prior comparative period, driven by the strength of the Australian dollar over the past 12 months. Little more detail on the segment results. Behring revenue was up 9%, gross profit up 10%, and EBIT up 24%, all at constant currency. This reflects the demand that Paul has talked about for ongoing demand for our therapies, but also reflects the management of costs during the pandemic period. You'll notice a 54% reduction in other revenue. This is largely attributable to lower GARDASIL royalties, driven by lower sales of GARDASIL by Merck, largely in the U.S., and a one-off favorable legal settlement that was reflected in the prior comparable period.
For Seqirus, total revenue was up 38% and EBIT up 112%, reflecting the strong demand for products that Paul talked about, the continued success of our product differentiation strategy, and the manufacturing efficiencies that we've realized through that increased production volume. These drivers are also reflected in gross profit, which saw an increase of 64% of constant currency and an expansion of gross margin of over 1,000 basis points. As was mentioned in August, at the full year, the Seqirus business has exceeded the long-range financial targets when Seqirus was first formed five years ago. I think everybody is now familiar with the seasonal nature of the business. The majority of sales are into the Northern Hemisphere and therefore reflected in the first half, whereas a lot of the costs of the business are more evenly spread throughout the year.
The upshot is that Seqirus, as it has in the past, will record a loss in the second half. Turning to expenses, walking through each of these items. R&D expense was down $ 24 million or 5%. It's largely due to the impact of COVID on the R&D portfolio. As Paul highlighted, we had amended some of the projects, slowed them down, reprioritized in order to redirect activity to COVID vaccines. However, with respect to the full year, we are still anticipating an R&D spend in the range previously guided of 10%-11% of sales. Sales and marketing expenses are down 6%, largely due to lower travel and marketing expenditure, again, due to the COVID outbreak. This is offset by an increase within Seqirus to support current and future growth, as well as entry to new market channels.
In general and admin, down 18%, largely a function of initiatives to control expenditure that were put in place in the environment of COVID uncertainty. The effective tax rate remains relatively steady at 20%, although for the full year, we do expect that to tick up to 22%. As closing comment, while the group's expenses have been contained, as the global pandemic recedes, we would expect to see a lift in costs as societal mobility resumes and the business returns to some semblance of normal operations. With that, I'll hand back to Paul.
Thanks, John. Returning now to slide 20. I'll make a few comments on our outlook for 2021 and beyond before taking questions. The first point to note is that the full-year result will be heavily skewed to the first half. For the second half of 2021, the seasonality of the Seqirus business means it will make a loss, as John mentioned. 80% of our sales are made in the first half, and the cost of goods, as John mentioned, are relatively evenly spread throughout the duration of the year. Sales of albumin will continue to normalize following the transition to the new business model in China, and the rate of growth in the second half on the first half will not be as strong. Plasma products sold in the second half arise from plasma collected last year in a COVID environment.
The higher cost of this plasma is expected to put some pressure on our margins. The additional work we've been doing on COVID-19 vaccines has resulted in the reprioritization of R&D projects, and subsequently, there'll be an increase in R&D spend in the second half as we restart the projects and build them back to scale. For the full year, we do anticipate a return to our long-term guidance of the 10%-11% of revenue, as John mentioned. Lastly, once COVID recedes and restrictions around social mobility are eased, we anticipate an increase in SG&A expenses. In terms of fiscal 2021 guidance, we affirm that profit after tax to be approximately $ 2.17 billion-$ 2.265 billion at constant currency. As per our usual practice, we'll be providing guidance for fiscal 2022 at our full year results announcements.
I'd like to finish up by making some general comments about the longer-term outlook for CSL. We continue to believe the underlying demand for IG will remain strong. As with the second half of 2021, plasma collected today drive our 2022 sales for IG and albumin. We expect our collections to grow as the pandemic recedes and society returns to the more normal social mobility norms, particularly noting the global community is on the cusp of a broad-based COVID vaccine rollout. However, this takes time, which means the impacts from COVID, both positive and negative, add a pretty heavy layer of complexity and uncertainty to our earnings profile until we get through this pandemic. COVID restrictions on social mobility have also inhibited patients' ability to visit doctors, access emergency services, and once these restrictions ease, we expect there will be an increase in product demand in general.
Lastly, our multiple large late-stage R&D programs underway provide potential new growth opportunities. I really do believe CSL is well-positioned to emerge strongly when this pandemic recedes.