Interview, Podcast
The Delta Variant: Implications for Vaccines, Booster Shots and Economic Growth
- Delta Variant Characteristics
- Delta is the globally predominant strain due to significantly higher transmissibility compared to prior variants (Alpha, etc.).
- Viral load in infected individuals is higher, allowing transmission over shorter exposure periods.
- Vaccinated individuals can become asymptomatically infected and transmit the virus, a departure from earlier strain dynamics.
- Vaccine Efficacy Against Delta
- Symptomatic Protection:
- Two doses of mRNA vaccines (Pfizer-BioNTech, Moderna) provide ~88% protection in the UK against symptomatic Delta infection.
- Efficacy against symptomatic infection dropped to ~40% in Israel, potentially due to waning immunity over time.
- Single-dose efficacy against Delta is significantly lower at approximately 30%.
- Severe Disease Protection:
- Efficacy against severe disease and hospitalization remains robust at ~90% across data from Israel and Canada, even with Delta.
- Breakthrough infections in fully vaccinated individuals are rare, with CDC data showing only 6,600 severe cases/deaths among 160 million vaccinated people through July 2021.
- Breakthrough infections generally result in milder symptoms (60% fewer flu-like symptoms) and shorter duration (two fewer days) than unvaccinated cases.
- Vaccine Platform Comparison:
- mRNA vaccines (Pfizer, Moderna) show slightly higher efficacy against symptomatic disease than adenoviral vectors (AstraZeneca, J&J).
- All four major vaccines demonstrate comparable high efficacy against hospitalization and severe disease.
- Symptomatic Protection:
- Booster Strategy and Development
- Rationale for Boosters: Needed primarily due to waning immunity in high-risk populations or the emergence of variants that evade current vaccine protection.
- Target Populations:
- High-risk groups (immunocompromised, elderly) are already receiving boosters in Israel, Germany, and France.
- Pfizer plans to file for an EUA with the FDA for a booster dose in August.
- Internal modeling suggests annual boosters for the elderly/high-risk and biennial boosters for younger adults.
- Future Formulations:
- Companies are developing "next-gen" vaccines tailored to specific variants (e.g., Delta, Beta) to ensure regulatory readiness.
- Long-term goal includes multivalent vaccines combining COVID-19 and seasonal flu shots.
- Global Economic Impact and Forecasts
- Europe:
- UK cases are down 50% from peak post-reopening; hospital admissions and PMI data suggest re-acceleration.
- Spain, Portugal, and the Netherlands are peaking or declining in cases; France, Italy, and Germany see rising cases but at low levels.
- Goldman Sachs remains bullish on Europe, citing room for vaccine-driven reopening.
- United States:
- Hospitalization rates vary drastically by vaccination rates: 1 in 2,000 in Florida vs. 1 in 100,000 in Vermont.
- Consumer risk aversion has increased despite vaccination; Gallup data shows protected sentiment dropped from 50% to 38%.
- Goldman Sachs lowered U.S. growth forecasts by shaving 2 percentage points off annualized consumption growth for the second half.
- Key headwinds include slower office return rates and persistent housing supply bottlenecks.
- Emerging Markets (EM):
- Latin America: Generally positive; cases declining and high natural immunity/vaccination rates. Goldman Sachs has upgraded forecasts.
- Asia-Pacific: Deteriorating situation due to lower natural immunity and late vaccination starts; sharp forecast cuts for Philippines, Thailand, and ASEAN.
- China: High uncertainty regarding the achievability of "zero COVID" amid rising cases of the more transmissible Delta variant.
- Europe:
- Revised Growth Outlook
- Global growth forecasts have been lowered since April, but the gap between Goldman Sachs estimates and market consensus has narrowed from ~1% to 0.3%.
- U.S. Specific Forecast: Growth expected to decelerate from ~7% this summer to a potential pace of 1.5%–2% in the second half of next year.
- Key Risks:
- Emergence of a new, more transmissible variant that significantly reduces vaccine efficacy against hospitalization.
- Slower recovery of the global supply side (goods sector and U.S. labor market) due to complex worker behavior changes and inventory rebuilding delays.