A new large-scale study, published in the Lancet, has found that the two-dose Pfizer-BioNTech COVID vaccine is “highly effective” at preventing hospitalizations for at least six months, according to The Guardian.

However, the study also found that the protection against COVID infection nearly halves over the same period.

The vaccine’s efficacy against the infection fell from 88% within a month of having two doses to 47% after six months, per the research. However, the efficacy against hospitalizations remained 90% for six months, effective against all variants, including the highly contagious Delta variant.

The study researchers said the findings underscore the importance of improving COVID vaccination rates across the world.

For instance, the NHS has already been offering booster (third) doses to people who had their second vaccine six months ago. In the United States, booster doses have been approved for people aged 60 and above and those who are prone to develop a serious illness.

Lead author Dr. Sara Tartof of the Kaiser Permanente Southern California Department of Research and Evaluation said, “Our study confirms that vaccines are a critical tool for controlling the pandemic and remain highly effective in preventing severe disease and hospitalization, including from the Delta and other variants of concern.”

Dr. Luis Jodar, Chief Medical Officer of Pfizer Vaccines, said, “Our variant-specific analysis clearly shows that the BNT162b2 vaccine is effective against all current variants of concern, including Delta. Covid-19 infections in people who have received two vaccine doses are most likely due to waning and not caused by Delta or other variants escaping vaccine protection.”

“This publication describes real-world evidence from the US on the effectiveness of the Pfizer/BioNTech vaccine assessed using data from a large healthcare database from the Kaiser Permanente organization, said Prof. Penny Ward of King’s College London, who was not part of the study.

Meanwhile, in the UK, experts believe that winter could see a surge in new infections, with nursing leaders warning that nurses are experiencing more sickness that could affect patient care.

The Royal College of Nursing (RCN) analyzed staff sickness before the pandemic and earlier this year. It found that thousands of days have been lost to staff absence on already overstretched wards.

Carol Popplestone, Vice-Chair of RCN Council, said, “There will be immense pressure on health and care services this winter, and services can’t afford to lose safety-critical professionals to avoidable illnesses on top of tens of thousands of nursing vacancies.” The story originally appeared in The Guardian.